Track shunting apparatus



Oct.l7, 193 9. QfHAGAN I 2,176,639

- TRACK-SHUNTING APPARATUS Filed Nov. 25, 1932 BXCY - INVENTOR BernardE. OZIagazz BY 032W HIS ATTORNEY Patented Oct. 17, 1939 TRACK SHUNTINGAPPARATUS Bernard E. OHagan, Swissvale, Pa, assignor to The Union Switch& Signal Company, Swissvale, Pa., a corporation of PennsylvaniaApplication November 25, 1932, Serial No. 644,180

23 Claims.

' My invention relates to track shunting apparatus, and morespecifically to apparatus .for shunting of track circuits by lightweight rail vehicles equipped with steel wheels or with pneumatic tiredwheels.

' I will describe one form of track shunting apparatus embodying myinvention, and will then point out the novel features thereof in claims.

The track shunting apparatus set forth in my present application issomewhat similar to that set forth in the copending application ofHoward A. Thompson, Serial No. 629,030, filed on August 16, 1932, forApparatus for decreasing rail contact resistance, and the said copendingapplication contains claims which cover broadly certain features of theinvention described in my present application.

The accompanying drawing is a diagrammatic view showing one form oftrack shunting apparatus embodying my invention, as applied to analternating current track circuit.

Referring to the drawing, I have shown a section of railway track ABprovided with a track relay TR at one end and having a track transformerT and a series reactor X at the other end of the section. The remainingapparatus which is illustrated is arranged to be carried on the railvehicle.

The reference character MG designates a motor generator set comprisingan alternating current generator G driven by a motor M which receivescurrent from the car battery CB. The transformer T at the forward end ofthe car has a primary winding 5 supplied with current from generator G,and two secondary windings B and 7 having substantially the same numberof turns. Winding 6 is connected across the two rails of the track bymeans of suitable contact shoes l and 2. Similarly, winding '8 isconnected to :the rails by means of contact shoes 3 and a. It will benoted that the polarities of these two windings are so chosen that withthe instantaneous polarities as indicated, the voltages of the windingswill be series-aiding and will be effective in causing a current tovflow over a path which may be traced from the plus terminal of winding6, winding 9 of transformer N contact shoes 2 and 3, winding 7, winding8 of transformer N contact shoes 4 and l, to the minus terminal ofwinding 6. Therefore, the voltage of both windings 6 and I will beeffective in breaking down any resistance film which may exist betweenthe contact shoes and the rails. It will be noted, however, that anyshunt current flowing between the two rails and supplied by transformerT will tions, thereby neutralizing the reactance of these windings andhence decreasing the shunt path 1 impedance to a minimum value.

In series with windings 6 and l are connected the primary windings 8 and9, respectively, of an indication transformer N which, when energized bythe rail film break-down current cause a voltage to be induced in thesecondary winding it which is used to energize a direct currentindication relay K through the rectifier R Windings 8 and 9 are soconnected that the fluxes caused by the current supplied from windings land 5 aid one another, whereas the fluxes through these windingsresulting from the shunt current flowing between the two rails opposeone another, with the result that the reactance of windings 8 and 9 isneutralized to decrease the impedance of these windings in an analogousmanner to that occurring in the case of windings 6 and l. When the filmbetween the contact shoes and the rails is broken down, the voltageinduced in winding it will be sufliciently high to maintain relay Kenergized, thereby closing an energizing circuit for the forward lamp Fof indicator L, to provide a visual indication to the car operator thatthe apparatus is providing a safe shunt to the track circuit.

The purpose of reactor X in series with winding 5 of transformer T is tolimit the maximum film breakdown current which can flow, in

. order to economize the output of generator G and consequently decreasethe drain on the car battery CB.

At the rear end of the car is provided a duplicate set of track shuntingapparatus so that adequate shunting protection will be available whenthe car is bridging insulated rail joints. The apparatus at the rear endof the car operates the rear indicating lamp R which provides a visualindication that this apparatus is functioning properly to shunt thetrack. At such times as the car is not bridging a rail joint, theapparatus at the rear end of the car provides increased shuntingprotection to the track circuit by making additional shunt pathseffective for deenergizing the track relay.

The frequency of the current supplied by generator G should besufiiciently far removed from the frequency of the track circuit sourceBX-CX to prevent false response of the track relay TR. It is notessential that alternating current be used for energizing windings 5 andH of transformers T and T as interrupted direct current, or periodicallyvaried current can also be used for inducing a film breakdown voltage inthe secondary windings of transformers T and T It will be apparent thatbecause of the neutralizing action of the fluxes caused by the shuntcurrents which flow in windings 6, 7, 8 and 9, the impedances of theshunt paths from rail to rail will consist chiefly of the resistances ofthe windings and their connections. Therefore, the shunting protectionprovided by the apparatus when used on an alternating current trackcircuit is substantially as effective as the protection which this.apparatus will provide on a direct current track circuit, therebyeliminating the necessity for using a separate system for each type oftrack circuit.

Considering the rail connections or windings 6 and I of transformer T itwill be noted that rail shoes I and 2, and 3 and 4 of the respectivewindings are not opposite each other with respect to the two rails, butare staggered in position. The purpose of this arrangement is to preventfeed-over from one track circuit to another when insulated rail jointsare located between the .rail shoes. For example, assuming insulatedrail joints to be located between shoes I and 4, and 3 and 2, it will beapparent that no closed electrical. circuit from rail to rail will bemade through either of windings 6, E. Therefore, there will be notransfer of current from one track circuit to another by means of theinductively coupled windings 6 and 7, thereby preventing possible falseenergization of a track relay by current froman adjoining track circuit.Although I have herein shown and described only one form of. trackshunting apparatus embodying my invention, it will be understood thatvarious changes and modifications may be made therein within the scopeof the appended claims .without departing from the spirit and scope ofmy invention.

Having thus described my invention, what I claim is:

1. In combination with a rail vehicle and a stretch of railway track, asource of varying current on said vehicle, a transformer on said vehiclehaving a primary Winding energized from said source and having twosecondary windings each of which is connected across the two rails ofthe track by means of rail contacts, the instantaneous polarities ofsaid contacts associated with either rail being opposite so that thevoltages of said two windings will aid each other in breaking down therail contact resistance to improve shunting of said track.

2. In combination with a rail vehicle and a stretch of railwaytrack, asource of varying current on said vehicle, a transformer on said vehiclehaving a primary winding energized from said source and having twosecondary windings each of which is connected across the two rails ofthe track by means of rail contacts in such manner that the voltages ofsaid two'windings are series-aiding for causing a current to flow over acircuit which includes one of said two windings, one pair of railcontacts and the rail portion therebetween, the other of said twowindings, and the other pair of rail contacts and the rail portiontherebetween, said current acting to break down the rail contactresistance to improve shunting of said track;

3. In combination with a rail vehicle and a stretch of railway track, asource of alternating current. track circuit energy and a track relayfor said stretch, another source, of. alternating.

current on said vehicle of such character as to be incapable ofoperating said track relay, and a transformer on said vehicle having aprimary winding energized from said other source and having twosecondary windings each of which has substantially the same number offlux linkages, the voltage of each of said two windings being appliedacross the two rails of said track by means of rail contacts forbreaking down the rail contact resistance, and the connections of saidtwo windings being so arranged that shunt currents from said trackcircuit source passing from one to the other rail through said railscontacts will flow in opposing directions in said two windings, therebytending to neutralize the reactan'ce thereof for decreasing the shuntimpedance to effect release of said track relay.

4. In combination with an alternating current track circuit, twoshunting paths from one to the other rail of. the track each of whichincludes a pair .of rail contacts and a winding energized inductivelyfrom a source of varying current for breakingdown the rail contactresistance, said windings being linked magnetically and wound in suchdirections that the alternating track circuit current flowing from oneto the other rail will set up opposing fluxes in said two windingsthereby decreasing the shunt impedance thereof to increase theeffectiveness of said two track shunting paths.

5. In combination with a rail vehicle and a stretch of railway track, asource of varying current on said vehicle; a transformer. on saidvehicle having a .primary and two secondary. windings; and fourconnections, one from the positive terminal of one of said two windingsto one rail of said track, a secondfrom the negative terminal of saidone Winding to.the other rail, a third from the positive terminal .ofthe other of said two windingsto said other rail, and a fourth fromthenegativeterminal of said other. winding to said one rail of, the track,.whereby rail contact resistance breakdown current will flow over aseries circuit ,whichincludes saidtwo windings and said .four railconnections, .and whereby two paths will be effective for shunting thetrack, each path includingone of .said two windings and thetworailconnections associated therewith.

6. Apparatus'for, shunting an alternating current track circuit:comprising in, combination, a rail vehicle, a sourceof varying currenton the vehicle of such character as to be. incapable of operating saidtrack circuit, a transformer on the vehicle having a primary windingenergized from said source,.a reactor in series with said primarywinding, two secondary windingson said transformer; a first pair of railcontacts,

one for each rail,one.contact being connected with the positive terminaland the other. contact being connected with the negative terminal of oneof said two; secondary windings; a second pair of rail contacts, .onefor-each rail, connected with the other of said two secondary windingsin such manner as to impress a voltage from rail to rail of oppositepolarity to that impressed by said one winding; an indicationtransformer having two primary windings and a secondary winding, one ofsaid two primary windings being connected in series with one of said twosecondary windings and the other of said two primary windings beingconnected in series with the other of said two secondary-windings insuch manner that the currents supplied by said two secondary windings tosaid two primary windings will set upgcumulative fluxes in saidindication transformer, and an indicator energized from the secondarywinding of said indication transformer.

'7. In combination with a rail vehicle and a stretch of railway track, asource of varying current on said vehicle, a transformer on said vehiclehaving a primary winding energized from said source and having twosecondary windings each of which is connected across the two rails ofthe track by means of rail contacts, the instantaneous polarities ofsaid contacts associated with either rail being opposite so that thevoltages of said two windings will aid each other in breaking down therail contact resistance to improve shunting of said track, the railcontacts associated with each of said two windings occupying a staggeredposition with respect to a line at right angles to the track therebypreventing the transfer of energy around an insulated rail joint at suchtimes as the rail joint is located between a pair of said rail contacts.

8. In combination with a rail vehicle and a stretch of railway track, asource of varying current, a transformer having a primary windingconnected with said source and having two secondary windings; and meansfor applying a rail film breakdown potential from one .of said sec--vondary windings across the two rails of said track at a first pair ofrail contacts and for applying a rail film breakdown potential from theother of said secondary windings across said two rails at a second pairof rail contacts.

9. In combination with a rail vehicle and a stretch of railway track, asource of current, two windings linked magnetically with each other,means for energizing said windings from said source, and means forapplying a rail film breakdown potential from one of said windingsacross the two rails of said track at a first pair of rail contacts andfor applying a rail film breakdown potential from the other of saidsecondary windings across said two rails at a second pair of railcontacts.

10. In combination with a stretch of railway track, a source of current,two pairs of rail contacts, each pair included in a shunt path from oneto the other rail of said track, and means for applying a rail filmbreakdown potential from said source across one of said contact pairs inone direction and across the other of said contact pairs in the reversedirection, whereby rail current will fiow between the contactsassociated with each rail 'for breaking down the rail contact resistanceto aid shunting of said track.

11. In combination with a stretch of railway track, two pairs of railcontacts, each pair included in a shunt path from one to the other railof said track, and means for applying a rail film breakdown potentialacross one of said contact pairs in one direction and across the otherof said contact pairs in the reverse direction, whereby rail currentwill flow between the contacts associated with each rail for breakingdown the rail contact resistance to aid shunting of said track.

12. In combination with a stretchof railway track, two pairs of railcontacts, each pair included in a shunt path from one to the other railof said track and the contacts of each pair occupying a staggeredposition with respect to a line at right angles to the track, and meansfor applying a rail film breakdown potential across one of said contactpairs in one direction and across the other of said contact pairs in thereverse direction, whereby rail current will flow between the contactsassociated with each rail for breaking down the rail contactlresistanceto aid shunting of said track.

13. In combination with a stretch of railway track, two pairs of railcontacts, each pair included in a shunt path from one to the other railof said track, means for applying a rail film breakdown potential acrossone of said contact pairs in one direction and across theother of saidcontact pairs in the reverse direction, whereby rail current will flowbetween the contacts associated with each rail for breaking down therail contact resistance to aid shunting of said track, and means forlimiting said breakdown current when said contact resistance has beenbroken down.

14. In combination with a stretch of railway track, two pairs of railcontacts, each pair included in a shunt path from one to the other railof said track, means for applying a rail film breakdown potential acrossone of said contact pairs in one direction and across the other of saidcontact pairs in the reverse direction, whereby rail current will fiowbetween the contacts associated with each rail for breaking down therail contact resistance to aid shunting of said track, and an impedancefor decreasing said film breakdown potential when said contactresistance has been broken down.

15. In combination with a rail vehicle and a stretch of railway track, asource of current on the vehicle, a track shunt, means for applying arail film breakdown potential from said source across the railcontacting portions of said track shunt to break down the rail contactresistance, and an impedance for limiting the amount of breakdowncurrent fiowing from said source when said contact resistance is brokendown.

16. In combination with a rail Vehicle and a stretch of railway track, asource of current on the vehicle, a track shunt, means for applying arail film breakdown potential from said source across the railcontacting portions of said track shunt to break down the rail contactresistance, and a reactor inserted between said source and said meansfor limiting the amount of breakdown current flowing from said sourcewhen said contact resistance is broken down.

1'7. In combination with a stretch of railway track, a source of varyingcurrent, transformer means energized from said source and having twowindings, and means for applying a rail film breakdown potential fromone of said windings across the two rails of said track at a first pairof rail contacts and for applying a rail film breakdown potential fromthe other of said windings across said two rails at a second pair ofrail contacts.

18. In combination with a stretch of railway track, a source of varyingcurrent, two transformers each energized from said source and eachhaving an output winding, and means for applying a rail film breakdownpotential from one of said output windings across the two rails of saidtrack at a first pair of rail contacts and for applying a rail filmbreakdown potential from the other of said output windings across saidtwo rails at a second pair of rail contacts.

19. In combination with a rail vehicle and a stretch of railway track, asource of varying current on said vehicle, and transformer means on saidVehicle energized from said source and having two windings each of whichis connected across the two rails of the track by means of railcontacts, the instantaneous polarities of said contacts associated witheither rail being opposite so that the voltages of said two windingswill aid each other in breaking down the rail contact resistance toimprove shunting of said track.

20. In combination with a rail vehicle and a stretch of railway track, asource of varying cur rent on said vehicle, and two transformers on saidvehicle each energized from said source and each having a winding whichis connected across the two rails of the track by means of rail contactsthe instantaneous polarities of said contacts associated with eitherrail being opposite so that the voltages of said two windings will aideach other in breaking down the rail contact resistanc to imroveshunting of said track.

21. In combination with a rail vehicle and a stretch of railway track, asource of varying current on said vehicle, transformer means on saidvehicle energized from said source and having two output windings; andfour connections, one from the positive terminal of one said winding toone rail of said track, a second from the negative terminal of said onewinding to the other rail, a third from the positive terminal of theother said winding to said other rail, and a fourth from the negativeterminal of said other winding to said one rail of the track, wherebyrail contact resistance breakdown current will flow over a seriescircuit which includes said two windings and said four rail connections,and whereby two paths will be effective for shunting the track, eachpath incuding one of said two windings and the two rail connectionsassociated therewith.

22. In combination with a rail vehicle and a stretch of railway track, asource of varying current on said vehicle, two transformers on saidvehicle each energized from said source and each having an outputwinding; and four connections, one from the positive terminal of onesaid winding to one rail of said track, a second from the negativeterminal of said one winding to the other rail, a third from thepositive terminal of the other said winding to said other rail, and afourth from the negative terminal of said other winding to said one railof the track, whereby rail contact resistance breakdown current willflow over a series circuit which includes said two windings and saidfour rail connections, and whereby two paths will be efiective forshunting the track, each path including one of said two windings and thetwo rail connections associated therewith.

23. In combination with a rail vehicle and a stretch of railway track, asource of current on the vehicle, means for applying a rail filmbreakdown potential from said source across the two rails of said trackto break down the rail contact resistance, and a reactor for limitingthe amount of breakdown current flowing from said source when saidcontact resistance is broken down.

BERNARD E. OHAGAN.

